Cardiff Blues chairman Peter Thomas has warned out-of-contract stars Leigh Halfpenny and Sam Warburton that they are risking their careers - not just their international future - if they opt for a lucrative move overseas.

Both Halfpenny and Warburton, stars of Wales' recent Six Nations triumph and the British & Irish Lions' series victory over Australia, are out of contract with the Blues at the end of this season and are reportedly the subject of interest from several French clubs.

The Blues hope to retain the services of both players but they are unlikely to be able to match the figures on offer in France or England that have already lured the likes of their fellow internationals George North, Jamie Roberts, Dan Lydiate and Mike Phillips away from Wales.

The Welsh Rugby Union have promised an injection of extra financial support but both they and the Blues are aware that it will not bridge the gap. "The business model in Wales cannot afford the sort of figures being bandied about by some French clubs," Thomas told The Rugby Paper. "But they realise that if they do go, there will be a massive price.

"Look at Dan Lydiate. He will have played six matches for Racing before Leigh or Sam play one. Come the autumn internationals, the Welsh-based players will be in far better physical conditions. Their careers will be longer by staying in Wales."

Thomas is also convinced both players can cash-in on their profiles if they remain in the regional game. "There will also be lots of commercial opportunities because they are recognised wherever they go, unlike the centre of Paris where could be any Tom, Dick or Harry," he said.

"Leigh and Sam are as icons in Wales and Richie McCaw and Dan Carter are in New Zealand. They will be playing in the next World Cup because they've been looked after. We've got to do the same with our very best players and they know what's at stake at the World Cup in two years' time."

He added: "I am optimistic that between us, the player, the Blues and the Welsh Rugby Union, we will find a solution."